This Program, centered at the Harvard School of Public Health (HSPH), trains radiation biologists in an integrated program focused on radiation damage and injury responses at the molecular, cellular, tissue, and organismal levels. Because this information is ultimately used to establish exposure guidelines and protective measures for human populations, it is highly appropriate that the Program is centered at HSPH. Both predoctoral and postdoctoral training will be offered. The interdepartmental Program combines radiobiology research resources in laboratories at HSPH, the Harvard Medical School, and associated hospitals. Research training will include didactic and practical courses, special lectures and lecture series, research seminars, research conferences, journal clubs, and laboratory research experience supervised by senior investigators. Laboratory research will typically focus on an aspect of ongoing, funded projects, but provision will be made for exceptional students to follow avenues of their own innovation. The strength of the program is based on the broad experience of and the diverse research pursued by a critical mass of training Preceptors with expertise in the fields of radiation chemistry and biochemistry, cellular and molecular radiation biology, mutagenesis, carcinogenesis, cytogenetics, animal models, and radiation oncology. Predoctoral trainees will have a science background in physics, chemistry and/or biology. They must be acceptable to the Program Director and meet Harvard University admissions requirements. Postdoctoral trainees will be admitted by application to one of the training preceptors and with approval of an executive committee consisting of the Program Director and one Preceptor from each training unit. It is expected that admission will be competitive. Four predoctoral and eight postdoctoral positions will be available. Trainees will be expected to pursue research and academic careers in the fields of radiation biology and radiological science including radiation oncology, nuclear medicine, medical radiation physics, and radiation protection. Primary research facilities will include: the Department of Genetics and Complex Diseases, HSPH; Department of Radiation Oncology, Harvard Medical School, Massachusetts General Hospital, Brigham and Women's Hospital, Beth Israel Deaconess Hospital, and Dana-Farber Cancer Institute;and the Laboratory for Experimental Nuclear Medicine, Department of Radiology, Harvard Medical School. The program will be administered through HSPH. In addition to classrooms, seminar rooms, departmental and university libraries, students will have access to specialized radiation sources and a large number of fully equipped laboratories including cell and tissue culture facilities, imaging facilities, and facilities for animal care.